LinOTP is a solution for strong two-factor authentication with one time passwords. It features a modular architecture into which UserIdResolver, authentication, and OTP calculation modules can be plugged. It includes UserIdResolver modules for LDAP/AD, SQL, and flat file user databases, and authentication modules for PAM and RADIUS. New modules can be developed easily. Supported tokens are HMAC-OTP/HOTP (RFC 4226/ OATH compliant), Aladdin eToken PASS, eToken NG-OTP, Safeword Alpine, Yubikey, Google Authenticator, motp, SMS OTP/Mobile TAN, email token, and a Simple Pass token for users without token hardware. TOTP is supported, along with a new algorithm for daily passwords for applications not supporting RADIUS. OCRA tokens are supported to allow transaction signing in banking environments. CLI, Web, and GTK+ GUI clients are available for management. LinOTP features multi-client capability, redundancy, and a self-service portal. It has been used with PAM for local and SSH logins, Apache, VPN, and Windows Terminal Server, and is OATH certified.

nss-pam-ldapd is a Name Service Switch module and Pluggable Authentication Module using an LDAP server. It allows your LDAP server to provide user account, group, host name, alias, netgroup, and almost any other information that you would normally get from /etc flat files or NIS, and allows you to do authentication to an LDAP server.

The OATH Toolkit makes it easy to build one-time password authentication systems. It contains shared libraries, commandline tools, and a PAM module. Supported technologies include the event-based HOTP algorithm (RFC4226) and the time-based TOTP algorithm (RFC6238). OATH stands for Open AuTHentication, which is the organization which specifies the algorithms. For managing secret key files, the Portable Symmetric Key Container (PSKC) format described in RFC6030 is supported.

The HOTP Toolkit package contains tools that are useful when deploying the one-time password HOTP technology. It contains a shared library, a command-line tool to generate and validate one-time passwords, and a PAM module (pam_hotp) to make system login or SSH use HOTP one-time passwords for authentication.

pam_csync is a PAM module to provide roaming home directories for a user session. The authentication module verifies the identity of a user and triggers a synchronization using csync with the server on the first login and the last logout.

pam_ttylog is a PAM module to log console output of a login shell. pam_ttylog takes an approach that makes a script-like environment in the PAM session section of /bin/login. Thus, the log files are in a user-unreachable directory and have user-unreadable/unwritable permissions. As PAM module, it doesn't need to modify or replace the original /bin/login, getty, telnet, or libraries for its installation and operation.

loginx combines the functionality of getty, login, and xinit in one simple executable. It shows a curses-based password prompt and remembers the last logged in user for less typing. It starts X if .xinitrc is present, a plain shell otherwise.

dynalogin is a distributed two-factor authentication suite that combines a secure UNIX server and API with an Android soft token. Open standards (HOTP, TOTP, and soon OCRA) are used for one-time passwords. A C library is provided for inclusion in existing software and Web sites. OpenID (using SimpleID) is supported for Web applications and single sign on. PAM is supported for easy UNIX and LDAP integration (SASL, RADIUS, and JAAS in development). It works with Google Authenticator or the dynalogin Android application.